Boletus Edulis: [Characteristics, Cultivation, Harvesting]

Boletus edulis is a basidiomycete fungus, and the type species of the genus Boletus. From the order of the ballots.

Widely distributed in the Northern Hemisphere across Europe, Asia, and North America, it does not occur naturally in the Southern Hemisphere, although it has been introduced to southern Africa, Australia, New Zealand, and Brazil.

A number of closely related European fungi previously believed to be varieties or forms of B. edulis have been shown by molecular phylogenetic analysis to be distinct species, and others previously classified as separate species are cospecific with this species.

The western North American species commonly known as the California king boletus (Boletus edulis var. grandedulis) is a large, darker-colored variant that was first formally identified in 2007.

Characteristics of boletus

The fungus grows in deciduous and coniferous forests and tree plantations, forming symbiotic ectomycorrhizal associations with living trees by enveloping the tree’s underground roots with sheaths of fungal tissue.

Boletus produces fruiting bodies with spores on the ground in summer and autumn. The fruit body has a large brown cap that can sometimes reach 35 cm (14 in) in diameter and 3 kg (6 lb 10 oz) in weight.

Like other boletes, it has tubes extending down from the bottom of the cap, instead of gills; the spores escape when mature through openings in the tubes, or pores.

The pore surface of the fruit body of B. edulis is whitish when young, but ages to a greenish-yellow.

The stout stylet, or stalk, is white or yellowish, up to 25 cm tall and 10 cm thick, and partially covered with a raised network pattern, or reticulations.

Appreciated as an ingredient in various culinary dishes, Boletus edulis is an edible fungus highly appreciated in many kitchens, and is usually prepared and eaten in soups, pasta or risottos. The mushroom is low in fat and digestible carbohydrates, and is high in protein, vitamins, minerals, and dietary fiber.

Although it is sold commercially, it is very difficult to grow.

Where to grow boletus edulis

Available in autumn in central, southern and northern Europe, it is often dried, packaged and distributed throughout the world.

It retains its flavor after drying, and is then reconstituted and used in cooking. B. edulis is one of the few mushrooms that are sold pickled.

Boletus edulis grow in numerous parts of the global world, symbiotically with both deciduous and coniferous, so they are constantly growing somewhere.

They start in mid- summer in a few mountain ranges (searching for sandy soils), disappear in the height of summer heat (August), and then begin to appear in greater abundance in the fall (appearance for dark fertile soils), especially on the coast. northwest where we harvest in western Canada.

Although they grow in many forms of forests, 100% of our harvests have been in coniferous forests (pine and spruce).

The relationship between trees and boletus edulis

Many fungi, including boletus edulis, have a mycorrhizal relationship with certain forests, that is, they live in symbiosis.

Fungi colonize and nourish the root system associated with trees. They have been efficient in absorbing and storing water; as well as different nutrients that discharge into the roots as needed.

They convert substances that are otherwise useless to the soil and adjust nitrogen according to the needs of the tree. To do all this ongoing work and also to reproduce, they need fuel.

They get this fuel from their photosynthetic tree mates. However, not only is it one fungus that is rare on a tree, but the two species also become completely interconnected communities.

Older and larger trees pass the mycorrhizae to their saplings by expanding the fungal system and thus roads and underground pathways become more complex and much more sensitive.

A tree that is not healthy, about to dry out, or has an invasive insect can be detected and the parts begin to work together to restore well-being and balance.

It is a fascinating system of symbiosis and collaboration.

Some considerations if you are harvesting boletus edulis

Regardless of planning the right place and time, boletus edulis, Porcini, tend to be in the same zone as amanitas, the famous fairy tale hallucinogenic mushroom. We call this a sister fungus or an indicator.

Although amanitas are believed to be edible in some countries, we do not recommend that you collect them yourself. In any case, you can give thanks because you may find boletus edulis around.

Once you find a boletus edulis, you will usually find more nearby. The giants, while impressively heavy, will almost certainly contain worm, leave them alone and continue searching the area.

You will quickly tell with a touch of your knife or the tip of your hand whether they are soft and mushy or firm and intact when in an area of ​​boletus edulis.

As with all mushroom picking, use gloves, baskets, or bags that have airflow. One dirty mushroom makes a whole bucket dirty and means a lot more work later on.

For boletus edulis that are clean, slice close to the root or gently wiggle and pull until it breaks free of the ground. Clean the needles, the remains of the hat and shave the stem with a very sharp knife.

Can boletus edulis be confused with other mushrooms?

It can be confused with B. reticulatus, but it does not have a whitish margin, its color is uniform, and the cuticle is matte, dry and finely reticulated. It is also an excellent edible.

Also with Boletus aereus and Boletus pinicola, excellent foodstuffs.

boletus edulis species

Several similar brown species are sometimes considered subspecies or forms of the boletus. In Europe, in addition to B. edulis (or cèpe de Bordeaux), the most popular are:

Tête de nègre («black’s head»; Boletus aereus)

Much rarer than B. edulis, it is more appreciated by gourmets and therefore more expensive. Normally smaller than B. edulis, it is also distinctively darker in color.

It is especially suitable for drying.

Cèpe des pins («pine cep»; Boletus pinophilus or Boletus pinicola)

It grows among the pines. Rarer than B. edulis, it is less prized by gourmets than the other two classes of porcine, but it is still a fungus ranked above most others.

Cèpe d’été («summer cep»; Boletus reticulatus)

Also less common.

Molecular phylogenetic analyzes have shown that these three are distinct and separate species; other taxa previously believed to be single species or subspecies, such as B. betulicola, B. chippewaensis, B. persoonii, B. quercicola, and B. venturii, are now known to be part of a B. edulis with a wide morphological range, ecological and geographical, and that the genetic variability in this complex is low.

Similar molecular technology has been developed to rapidly and accurately identify B. edulis and other commercially important fungi.

Three divergent lineages found in China’s Yunnan province that are commonly traded and sold as B. edulis (and are actually more closely related to B. aereus) were described in 2013 as B. bainiugan, B. meiweiniuganjun, and B. shiyong.

In western North America there are several species closely related to B. edulis.

The white king boletus (Boletus barrowsii)

Found in parts of Colorado, New Mexico, Arizona, and California (and possibly elsewhere), it is named for its discoverer Chuck Barrows.

It is lighter in color than B. edulis, and has a cream-colored cap with pink tinges; often mycorrhizal with Ponderosa pine, it tends to grow in areas where there is less rainfall. Some find its flavor as good as if it were no better than that of B. edulis.

The boletus edulis var. grandedulis from California can attain massive proportions, and is distinguished from B. edulis by a mature pore surface that is brownish to slightly reddish in color.

Cap color appears to be affected by the amount of light received during development, and can range from white in young individuals growing under a thick canopy, to dark brown, reddish brown, or yellowish brown in individuals receiving more light. light.

The queen boletus (Boletus regineus)

Formerly considered a variety of B. aereus, it is also a food of choice. It is generally smaller than B. edulis and, unlike that species, is typically found in mixed forests.

The spring king boletus (Boletus rex-veris), formerly considered a variety of B. edulis or B. pinophilus, is found throughout western North America. Unlike B. edulis, B. rex-veris tends to fruit in clusters and, as its common name suggests, appears in spring.

Pests and diseases of boletus edulis

The fruit bodies of Boletus edulis can be infected by the parasitic mold-like fungus Hypomyces chrysospermus, known as the eater bolete, which manifests as a white, yellow, or reddish-brown cottony coating on the surface of the fungus.

Some reported cases of stomach pain after consumption of dried pigs have been attributed to the presence of this mold on the fruit bodies.

The fungus is also used as a food source by several species of fungus gnats, as well as other insects and their larvae.

An unidentified species of virus was reported to have infected specimens found in the Netherlands and Italy; fruit bodies affected by the virus had relatively thick stems and small or no caps, giving rise to the name «little cap disease».

Boletus edulis is a food source for animals such as the banana slug (Ariolimax columbianus), the long-haired grass mouse, the red squirrel, and, as noted in an isolated report, the house sparrow.